Bifidobacterium(Nitto Pharmaceutical Industries Ltd.)

The disorder of the “gut-kidney axis” exacerbates renal function decline in chronic kidney disease (CKD), and current CKD therapy is insufficient to address this issue. Hirudin has a palliative effect on the decline of renal function. However, whether hirudin can delay CKD by regulating the “intestinal renal axis” disorder remains unclear. Unilateral ureteral ligation (UUO) induced CKD rat model, and the rats were treated with bifidobacterium and hirudin for 36 days. After 14 and 36 days of modeling, kidney and colon tissues were collected for pathology, western blot (WB) assay, and quantitative real-time PCR (qPCR) detection. Serum samples were collected for renal function testing. Fecal samples were used for 16S rRNA sequencing and research on fecal bacterial transplantation. Lipopolysaccharide combine with adenosine 5’-triphosphate (LPS + ATP)-induced intestinal epithelial cell injury was treated with a nod-like receptor pyrin domain-associated protein 3 (NLRP3) inhibitor and hirudin. Protein expression was detected using WB and qPCR. The kidneys and colons of the CKD rats exhibited varying degrees of lesions. Creatinine (CRE), blood urea nitrogen (BUN), N-acetyl-β-D-glucosidase (NAG) enzyme, and serum uremic toxins were elevated. The expression of claudin-1 and occludin was decreased, NLRP3 inflammatory-related proteins were increased, and the gut microbiota was disrupted. These pathological changes were more pronounced after 36 days of modeling. Meanwhile, high-dose hirudin treatment significantly improved these lesions and restored the intestinal flora to homeostasis in CKD rats. In vitro, hirudin demonstrated comparable effects to NLRP3 inhibitors by upregulating claudin-1 and occludin expression, and downregulating NLRP3 inflammatory-related proteins expression. The dysbiosis of the gut microbiota and impaired intestinal epithelial barrier function in CKD are associated with renal dysfunction in CKD. Hirudin delays the progression of CKD by regulating the disorder of the “gut-kidney axis” and inhibiting the activation of the NLRP3-ASC-caspase-1 pathway.

Alzheimer's disease (AD), the most prevalent type of dementia, still lacks disease-modifying treatment strategies. Recent evidence indicates that maintaining gut microbiota homeostasis plays a crucial role in AD. Targeted regulation of gut microbiota, including probiotics, is anticipated to emerge as a potential approach for AD treatment. However, the efficacy and mechanism of multi-strain probiotics treatment in AD remain unclear.

In this study, 6-month-old senescence-accelerated-mouse-prone 8 (SAMP8) and senescence-accelerated-mouse-resistant 1 (SAMR1) were utilized. The SAMP8 mice were treated with probiotic-2 (P2, a probiotic mixture of Bifidobacterium lactis and Lactobacillus rhamnosus) and probiotic-3 (P3, a probiotic mixture of Bifidobacterium lactis, Lactobacillus acidophilus, and Lactobacillus rhamnosus) (1 × 10⁹ colony-forming units) once daily for 8 weeks. Morris water maze (MWM) and novel object recognition (NOR) tests were employed to assess the memory ability. 16S sequencing was applied to determine the composition of gut microbiota, along with detecting serum short-chain fatty acids (SCFAs) concentrations. Neural injury, Aβ and Tau pathology, and neuroinflammation level were assessed through western blot and immunofluorescence. Finally, potential molecular mechanisms was explored through transcriptomic analysis and western blotting.

The MWM and NOR test results indicated a significant improvement in the cognitive level of SAMP8 mice treated with P2 and P3 probiotics compared to the SAMP8 control group. Fecal 16S sequencing revealed an evident difference in the α diversity index between SAMP8 and SAMR1 mice, while the α diversity of SAMP8 mice remained unchanged after P2 and P3 treatment. At the genus level, the relative abundance of ten bacteria differed significantly among the four groups. Multi-strain probiotics treatment could modulate serum SCFAs (valeric acid, isovaleric acid, and hexanoic acid) concentration. Neuropathological results demonstrated a substantial decrease in neural injury, Aβ and Tau pathology and neuroinflammation in the brain of SAMP8 mice treated with P3 and P2. Transcriptomic analysis identified the chemokine signaling pathway as the most significantly enriched signaling pathway between SAMP8 and SAMR1 mice. Western blot test indicated a significant change in the phosphorylation level of downstream AKT/GSK-3β between the SAMP8 and SAMR1 groups, which could be reversed through P2 and P3 treatment.

Multi-strain probiotics treatment can ameliorate cognitive impairment and pathological change in SAMP8 mice, including neural damage, Aβ and Tau pathology, and neuroinflammation. This effect is associated with the regulation of the phosphorylation of the AKT/GSK-3β pathway.